View clinical trials related to Endothelial Function.
Filter by:This study is to assess the function of blood vessels while being treated with different types of blood thinners to determine the effect of these medications on blood vessels.
The purpose of this study is to determine whether interventions aimed at increasing sympathetic tone modify endothelial function measures as assessed by the measurement of flow-mediated dilation (FMD) and constriction (FMC). The investigators hypothesize that the three interventions under study will increase FMC while causing a blunting in FMD. Further, the investigators plan to study the circadian variability of FMC and FMD. The investigators hypothesize a peak of FMD in the late hours of the day and a peak of FMC in the early hours.
Introduction: Cycling is currently promoted at the municipal, provincial and national level as a form of active transportation that increases physical activity while at the same time reducing traffic congestion, traffic-related air pollution and greenhouse gas emissions. While at a population level the health benefits of exercise via cycling are estimated to substantially exceed any health impacts related to air pollution exposure and injuries from traffic accidents , cyclists are known to experience elevated exposures to traffic-related air pollutants. Combined with exposure to elevated concentrations of air pollutants, cyclists also are subject to substantially increased inhaled doses due to their level of exertion and consequently increased inhalation rate. Therefore, given that cyclists experience exposures to relatively high concentrations of traffic-related air pollutants and that their inhalation of these pollutants is increased, it is important to evaluate the potential health impacts of this scenario. Research on the potential health impacts related to exercise (cycling) and urban air pollution exposure can help inform public communication strategies related to air quality and its health impacts. In addition, as our previous work suggests substantial variability in air pollution exposures to cyclists that is related to the route type and the levels of traffic along cycling routes, there is potential for transportation planners to promote increased cycling by enhancing infrastructure while at the same time developing routes that also minimize exposure to air pollution. The cyclist population is also interested in information regarding the air pollution exposures and potential health impacts related to cycling. The objective of this study is to investigate the relationship between traffic-related air pollution exposure, and respiratory and cardiovascular health impacts in commuting cyclists. Specifically, the investigators propose to: 1. determine commuting cyclists' exposure to traffic-related air pollutants (PM 2.5, PM10, ultrafine particulate, black carbon) while cycling along two different bicycle routes in the city of Vancouver; 2. estimate the pollutant dose received by each cyclist, and relate this to the health effects observed; and 3. determine if there is a change in lung function, endothelial function, and C-reactive protein level related to the level of air pollution exposure and dose
In acute myocardial infarction early restoration of coronary blood flow is the most effective strategy to limit infarct-size. Paradoxically, reperfusion itself also aggravates myocardial injury and contributes to final infarct size, a process termed 'reperfusion injury'. Ischemia and reperfusion (IR)-induced endothelial dysfunction seems to play a pivotal role in this process, resulting in vasoconstriction and reduced blood flow to the already ischemic tissue. Recently, it has been shown that the glucose-lowering drug metformin is able to limit IR-injury in murine models of myocardial infarction, probably by increased formation of the endogenous nucleoside adenosine. In the current research proposal, the investigators aim to translate this finding to the human in vivo situation, using flow-mediated dilation (FMD) of the brachial artery as a well-validated model of (endothelial) IR-injury.
The investigators hypothesize that, among non-hypertensive overweight and obese individuals, treatment of vitamin D deficiency and lowering uric acid concentrations (by either xanthine oxidase inhibition or increased renal excretion) will attenuate renin angiotensin system (RAS) activation, improve endothelial function, and lower blood pressure.
The purpose of this study is to evaluate the ability of portable high efficiency particle air (HEPA) filters to reduce exposures to PM2.5 and woodsmoke air pollution indoors and to improve subclinical indicators of microvascular function, systemic inflammation, and oxidative stress among healthy adult participants.
Nebivolol is a novel blood pressure lowering drug with an additional effect on the inner lining of blood vessels to release a compound called nitric oxide that can relax blood vessels. Atenolol is a blood pressure reducing agent without the ability to release nitric oxide and effect additional blood vessel relaxation. The goal of this proposal is to compare Nebivolol and Atenolol with respect to the following parameters: - Plaque within arteries supplying the heart in terms of its volume and composition as assessed by ultrasound within these arteries. - Ability of small arteries in the heart to open up and deliver an enhanced blood supply in response to drug called Adenosine (routinely used in the cardiac catheterization laboratory) as assessed by pressure and flow detecting catheters within these arteries. - Ability of the inner lining of arteries that supply the heart to release a relaxing compound called nitric oxide in response to injection of Acetylcholine (also used in the cardiac catheterization laboratory) as assessed by squirting dye into these arteries - Local forces that affect blood flow in the arteries supplying the heart as assessed by superimposing the above data into complex maps created offline at Georgia Institute of Technology. It is likely that Nebivolol causes the plaque within arteries supplying the heart to change from the 'vulnerable' type to the 'stable' type plaque. There are several features of "vulnerable plaques" that can be detected in arteries of the heart using intravascular ultrasound (a small ultrasound camera that goes in the arteries of the heart). The investigators hypothesis is that Nebivolol will prove superior to Atenolol in reducing 'vulnerable plaques', improve blood flow within the small arteries and the health of inner lining of these arteries at the 1 year time point. The investigators plan to enroll 20 patients into the study (26 patient including dropouts) who will be randomized in a 1:1 manner to Nebivolol Vs Atenolol for 1 year and repeat evaluation at that time point.
Context: Soluble CD40 ligand (sCD40L) released from activated platelets induces inflammatory transformation of the vascular endothelium and is an independent predictor of cardiovascular events. Arterial hypertension is associated with platelet activation, increased sCD40L levels and endothelial dysfunction suggesting that inhibition of platelet-derived sCD40L release may improve endothelial function and lower blood pressure (BP). Objective: To determine the effects of clopidogrel on sCD40L, endothelial function and BP. Design: Randomized, controlled, investigator-blinded, parallel-group, 2-phase trial in patients with coronary artery disease and essential arterial hypertension and those without hypertension. Intervention: Participants receive a single 600-mg clopidogrel loading dose (phase I) followed by a daily 75-mg clopidogrel maintenance dose over 28 days (phase II). Outcome Measures: Primary outcome measure is the change in BP from baseline. Secondary outcome measures are changes in biomarkers of platelet and endothelial function and their correlation with BP.
The general objective of the study is to investigate the effects of the daily consumption of spices and herbs for four (4) consecutive weeks in endothelial function and cardiovascular risk factors of men and postmenopausal women.
This investigation is interested in the effects of high dose vitamin C on endothelial function in healthy humans. A high fat meal will be utilized to induce endothelial dysfunction. It is hypothesized that, via antioxidant actions, vitamin C will reverse these effects and in turn improve blood flow- the involvement of nitric oxide suggests that this could extend to cerebral blood flow. This will be monitored by trans cranial doppler flow meter and near infrared spectroscopy.